form: Add Form and FormField. (#565)

<img width="899" alt="image"
src="https://github.com/user-attachments/assets/842dac65-36c3-4f3a-b55a-59d204d9a93c"
/>
<img width="901" alt="image"
src="https://github.com/user-attachments/assets/616b7a3a-4a84-4d27-b554-63ebd5213ad7"
/>

crates/story/src/dropdown_story.rs

@@ -206,7 +206,7 @@ impl DropdownStory {
 }
 
 impl FocusableCycle for DropdownStory {
-    fn cycle_focus_handles(&self, cx: &mut ViewContext<Self>) -> Vec<gpui::FocusHandle>
+    fn cycle_focus_handles(&self, cx: &mut WindowContext) -> Vec<gpui::FocusHandle>
     where
         Self: Sized,
     {

crates/story/src/form_story.rs

@@ -0,0 +1,202 @@
+use gpui::{
+    actions, div, Axis, InteractiveElement, IntoElement, ParentElement as _, Render, Styled, View,
+    ViewContext, VisualContext, WindowContext,
+};
+use ui::{
+    button::{Button, ButtonGroup},
+    date_picker::DatePicker,
+    divider::Divider,
+    form::{form_field, v_form},
+    h_flex,
+    input::TextInput,
+    prelude::FluentBuilder as _,
+    switch::Switch,
+    v_flex, AxisExt, FocusableCycle, Selectable, Sizable, Size,
+};
+
+actions!(input_story, [Tab, TabPrev]);
+
+pub struct FormStory {
+    name_input: View<TextInput>,
+    email_input: View<TextInput>,
+    bio_input: View<TextInput>,
+    subscribe_email: bool,
+    date_picker: View<DatePicker>,
+    layout: Axis,
+    size: Size,
+}
+
+impl super::Story for FormStory {
+    fn title() -> &'static str {
+        "FormStory"
+    }
+
+    fn closable() -> bool {
+        false
+    }
+
+    fn new_view(cx: &mut WindowContext) -> View<impl gpui::FocusableView> {
+        Self::view(cx)
+    }
+}
+
+impl FormStory {
+    pub fn view(cx: &mut WindowContext) -> View<Self> {
+        cx.new_view(Self::new)
+    }
+
+    fn new(cx: &mut ViewContext<Self>) -> Self {
+        let name_input = cx.new_view(|cx| {
+            let mut input = TextInput::new(cx).cleanable();
+            input.set_text("Jason Lee", cx);
+            input
+        });
+
+        let email_input = cx.new_view(|cx| TextInput::new(cx).placeholder("Enter text here..."));
+        let bio_input = cx.new_view(|cx| {
+            let mut input = TextInput::new(cx)
+                .multi_line()
+                .rows(10)
+                .placeholder("Enter text here...");
+            input.set_text("Hello 世界，this is GPUI component.", cx);
+            input
+        });
+        let date_picker = cx.new_view(|cx| DatePicker::new("birthday", cx));
+
+        Self {
+            name_input,
+            email_input,
+            bio_input,
+            date_picker,
+            subscribe_email: false,
+            layout: Axis::Vertical,
+            size: Size::default(),
+        }
+    }
+}
+
+impl FocusableCycle for FormStory {
+    fn cycle_focus_handles(&self, cx: &mut WindowContext) -> Vec<gpui::FocusHandle>
+    where
+        Self: Sized,
+    {
+        vec![
+            self.name_input.focus_handle(cx),
+            self.email_input.focus_handle(cx),
+            self.bio_input.focus_handle(cx),
+        ]
+    }
+}
+
+impl gpui::FocusableView for FormStory {
+    fn focus_handle(&self, cx: &gpui::AppContext) -> gpui::FocusHandle {
+        self.name_input.focus_handle(cx)
+    }
+}
+
+impl Render for FormStory {
+    fn render(&mut self, cx: &mut ViewContext<Self>) -> impl IntoElement {
+        v_flex()
+            .id("form-story")
+            .size_full()
+            .p_4()
+            .justify_start()
+            .gap_3()
+            .child(
+                h_flex()
+                    .gap_3()
+                    .flex_wrap()
+                    .justify_between()
+                    .child(
+                        Switch::new("layout")
+                            .checked(self.layout.is_horizontal())
+                            .label("Horizontal")
+                            .on_click(cx.listener(|this, checked: &bool, cx| {
+                                if *checked {
+                                    this.layout = Axis::Horizontal;
+                                } else {
+                                    this.layout = Axis::Vertical;
+                                }
+                                cx.notify();
+                            })),
+                    )
+                    .child(
+                        ButtonGroup::new("size")
+                            .small()
+                            .child(
+                                Button::new("large")
+                                    .selected(self.size == Size::Large)
+                                    .child("Large"),
+                            )
+                            .child(
+                                Button::new("medium")
+                                    .child("Medium")
+                                    .selected(self.size == Size::Medium),
+                            )
+                            .child(
+                                Button::new("small")
+                                    .child("Small")
+                                    .selected(self.size == Size::Small),
+                            )
+                            .on_click(cx.listener(|this, selecteds: &Vec<usize>, cx| {
+                                if selecteds.contains(&0) {
+                                    this.size = Size::Large;
+                                } else if selecteds.contains(&1) {
+                                    this.size = Size::Medium;
+                                } else if selecteds.contains(&2) {
+                                    this.size = Size::Small;
+                                }
+                                cx.notify();
+                            })),
+                    ),
+            )
+            .child(Divider::horizontal())
+            .child(
+                v_form()
+                    .layout(self.layout)
+                    .with_size(self.size)
+                    .child(
+                        form_field()
+                            .label_fn(|_| "Name")
+                            .child(self.name_input.clone()),
+                    )
+                    .child(
+                        form_field()
+                            .label("Email")
+                            .child(self.email_input.clone())
+                            .required(true),
+                    )
+                    .child(
+                        form_field()
+                            .label("Bio")
+                            .when(self.layout.is_vertical(), |this| this.items_start())
+                            .child(self.bio_input.clone())
+                            .description_fn(|_| {
+                                div().child("Use at most 100 words to describe yourself.")
+                            }),
+                    )
+                    .child(
+                        form_field()
+                            .no_label_indent()
+                            .child("This is a full width form field."),
+                    )
+                    .child(
+                        form_field()
+                            .label("Birthday")
+                            .child(self.date_picker.clone())
+                            .description("Select your birthday, we will send you a gift."),
+                    )
+                    .child(
+                        form_field().child(
+                            Switch::new("subscribe-newsletter")
+                                .label("Subscribe our newsletter")
+                                .checked(self.subscribe_email)
+                                .on_click(cx.listener(|this, checked: &bool, cx| {
+                                    this.subscribe_email = *checked;
+                                    cx.notify();
+                                })),
+                        ),
+                    ),
+            )
+    }
+}

crates/story/src/input_story.rs

@@ -323,7 +323,7 @@ impl InputStory {
 }
 
 impl FocusableCycle for InputStory {
-    fn cycle_focus_handles(&self, cx: &mut ViewContext<Self>) -> Vec<FocusHandle> {
+    fn cycle_focus_handles(&self, cx: &mut WindowContext) -> Vec<FocusHandle> {
         [
             self.input1.focus_handle(cx),
             self.input2.focus_handle(cx),

crates/story/src/lib.rs

@@ -3,6 +3,7 @@ mod assets;
 mod button_story;
 mod calendar_story;
 mod dropdown_story;
+mod form_story;
 mod icon_story;
 mod image_story;
 mod input_story;
@@ -25,6 +26,14 @@ pub use accordion_story::AccordionStory;
 pub use button_story::ButtonStory;
 pub use calendar_story::CalendarStory;
 pub use dropdown_story::DropdownStory;
+pub use form_story::FormStory;
+
+use gpui::{
+    actions, div, prelude::FluentBuilder as _, px, AnyElement, AnyView, AppContext, Context as _,
+    Div, EventEmitter, FocusableView, Global, Hsla, InteractiveElement, IntoElement, Model,
+    ParentElement, Render, SharedString, StatefulInteractiveElement, Styled as _, View,
+    ViewContext, VisualContext, WindowContext,
+};
 pub use icon_story::IconStory;
 pub use image_story::ImageStory;
 pub use input_story::InputStory;
@@ -42,13 +51,6 @@ pub use text_story::TextStory;
 pub use tooltip_story::TooltipStory;
 pub use webview_story::WebViewStory;
 
-use gpui::{
-    actions, div, prelude::FluentBuilder as _, px, AnyElement, AnyView, AppContext, Context as _,
-    Div, EventEmitter, FocusableView, Global, Hsla, InteractiveElement, IntoElement, Model,
-    ParentElement, Render, SharedString, StatefulInteractiveElement, Styled as _, View,
-    ViewContext, VisualContext, WindowContext,
-};
-
 use ui::{
     button::Button,
     divider::Divider,
@@ -298,6 +300,7 @@ impl StoryState {
             "WebViewStory" => story!(WebViewStory),
             "AccordionStory" => story!(AccordionStory),
             "SidebarStory" => story!(SidebarStory),
+            "FormStory" => story!(FormStory),
             _ => {
                 unreachable!("Invalid story klass: {}", self.story_klass)
             }

crates/story/src/main.rs

@@ -4,10 +4,10 @@ use prelude::FluentBuilder as _;
 use serde::Deserialize;
 use std::{sync::Arc, time::Duration};
 use story::{
-    AccordionStory, AppState, Assets, ButtonStory, CalendarStory, DropdownStory, IconStory,
-    ImageStory, InputStory, ListStory, ModalStory, PopupStory, ProgressStory, ResizableStory,
-    ScrollableStory, SidebarStory, StoryContainer, SwitchStory, TableStory, TextStory,
-    TooltipStory,
+    AccordionStory, AppState, Assets, ButtonStory, CalendarStory, DropdownStory, FormStory,
+    IconStory, ImageStory, InputStory, ListStory, ModalStory, PopupStory, ProgressStory,
+    ResizableStory, ScrollableStory, SidebarStory, StoryContainer, SwitchStory, TableStory,
+    TextStory, TooltipStory,
 };
 use ui::{
     badge::Badge,
@@ -318,6 +318,7 @@ impl StoryWorkspace {
                     Arc::new(StoryContainer::panel::<ScrollableStory>(cx)),
                     Arc::new(StoryContainer::panel::<AccordionStory>(cx)),
                     Arc::new(StoryContainer::panel::<SidebarStory>(cx)),
+                    Arc::new(StoryContainer::panel::<FormStory>(cx)),
                     // Arc::new(StoryContainer::panel::<WebViewStory>(cx)),
                 ],
                 None,

crates/ui/src/focusable.rs

@@ -1,4 +1,4 @@
-use gpui::{FocusHandle, ViewContext};
+use gpui::{FocusHandle, WindowContext};
 
 /// A trait for views that can cycle focus between its children.
 ///
@@ -8,13 +8,13 @@ use gpui::{FocusHandle, ViewContext};
 /// should be cycled, and the cycle will follow the order of the list.
 pub trait FocusableCycle {
     /// Returns a list of focus handles that should be cycled.
-    fn cycle_focus_handles(&self, cx: &mut ViewContext<Self>) -> Vec<FocusHandle>
+    fn cycle_focus_handles(&self, cx: &mut WindowContext) -> Vec<FocusHandle>
     where
         Self: Sized;
 
     /// Cycles focus between the focus handles returned by `cycle_focus_handles`.
     /// If `is_next` is `true`, it will cycle to the next focus handle, otherwise it will cycle to prev.
-    fn cycle_focus(&self, is_next: bool, cx: &mut ViewContext<Self>)
+    fn cycle_focus(&self, is_next: bool, cx: &mut WindowContext)
     where
         Self: Sized,
     {

crates/ui/src/form.rs

@@ -0,0 +1,428 @@
+use std::rc::{Rc, Weak};
+
+use gpui::{
+    div, prelude::FluentBuilder as _, px, AlignItems, AnyElement, AnyView, Axis, Div, Element,
+    ElementId, FocusHandle, InteractiveElement as _, IntoElement, ParentElement, Pixels, Rems,
+    RenderOnce, SharedString, Styled, WindowContext,
+};
+
+use crate::{h_flex, v_flex, ActiveTheme as _, AxisExt, FocusableCycle, Sizable, Size, StyledExt};
+
+/// Create a new form with a vertical layout.
+pub fn v_form() -> Form {
+    Form::vertical()
+}
+
+/// Create a new form with a horizontal layout.
+pub fn h_form() -> Form {
+    Form::horizontal()
+}
+
+/// Create a new form field.
+pub fn form_field() -> FormField {
+    FormField::new()
+}
+
+#[derive(IntoElement)]
+pub struct Form {
+    fields: Vec<FormField>,
+    props: FieldProps,
+}
+
+#[derive(Clone, Copy)]
+struct FieldProps {
+    size: Size,
+    label_width: Option<Pixels>,
+    label_text_size: Option<Rems>,
+    layout: Axis,
+    /// Field gap
+    gap: Option<Pixels>,
+}
+
+impl Default for FieldProps {
+    fn default() -> Self {
+        Self {
+            label_width: Some(px(140.)),
+            label_text_size: None,
+            layout: Axis::Vertical,
+            size: Size::default(),
+            gap: None,
+        }
+    }
+}
+
+impl Form {
+    fn new() -> Self {
+        Self {
+            props: FieldProps::default(),
+            fields: Vec::new(),
+        }
+    }
+
+    /// Creates a new form with a horizontal layout.
+    pub fn horizontal() -> Self {
+        Self::new().layout(Axis::Horizontal)
+    }
+
+    /// Creates a new form with a vertical layout.
+    pub fn vertical() -> Self {
+        Self::new().layout(Axis::Vertical)
+    }
+
+    /// Set the layout for the form, default is `Axis::Vertical`.
+    pub fn layout(mut self, layout: Axis) -> Self {
+        self.props.layout = layout;
+        self
+    }
+
+    /// Set the width of the labels in the form. Default is `px(100.)`.
+    pub fn label_width(mut self, width: Pixels) -> Self {
+        self.props.label_width = Some(width);
+        self
+    }
+
+    /// Set the text size of the labels in the form. Default is `None`.
+    pub fn label_text_size(mut self, size: Rems) -> Self {
+        self.props.label_text_size = Some(size);
+        self
+    }
+
+    /// Set the gap between the form fields.
+    pub fn gap(mut self, gap: Pixels) -> Self {
+        self.props.gap = Some(gap);
+        self
+    }
+
+    /// Add a child to the form.
+    pub fn child(mut self, field: impl Into<FormField>) -> Self {
+        self.fields.push(field.into());
+        self
+    }
+
+    /// Add multiple children to the form.
+    pub fn children(mut self, fields: impl IntoIterator<Item = FormField>) -> Self {
+        self.fields.extend(fields);
+        self
+    }
+}
+
+impl Sizable for Form {
+    fn with_size(mut self, size: impl Into<Size>) -> Self {
+        self.props.size = size.into();
+        self
+    }
+}
+
+impl FocusableCycle for Form {
+    fn cycle_focus_handles(&self, _: &mut WindowContext) -> Vec<FocusHandle>
+    where
+        Self: Sized,
+    {
+        self.fields
+            .iter()
+            .filter_map(|item| item.focus_handle.clone())
+            .collect()
+    }
+}
+
+pub enum FieldBuilder {
+    String(SharedString),
+    Element(Rc<dyn Fn(&mut WindowContext) -> AnyElement>),
+    View(AnyView),
+}
+
+impl Default for FieldBuilder {
+    fn default() -> Self {
+        Self::String(SharedString::default())
+    }
+}
+
+impl From<AnyView> for FieldBuilder {
+    fn from(view: AnyView) -> Self {
+        Self::View(view)
+    }
+}
+
+impl RenderOnce for FieldBuilder {
+    fn render(self, cx: &mut WindowContext) -> impl IntoElement {
+        match self {
+            FieldBuilder::String(value) => value.into_any_element(),
+            FieldBuilder::Element(builder) => builder(cx),
+            FieldBuilder::View(view) => view.into_any(),
+        }
+    }
+}
+
+impl From<&'static str> for FieldBuilder {
+    fn from(value: &'static str) -> Self {
+        Self::String(value.into())
+    }
+}
+
+impl From<String> for FieldBuilder {
+    fn from(value: String) -> Self {
+        Self::String(value.into())
+    }
+}
+
+impl From<SharedString> for FieldBuilder {
+    fn from(value: SharedString) -> Self {
+        Self::String(value)
+    }
+}
+
+#[derive(IntoElement)]
+pub struct FormField {
+    id: ElementId,
+    form: Weak<Form>,
+    label: Option<FieldBuilder>,
+    no_label_indent: bool,
+    focus_handle: Option<FocusHandle>,
+    description: Option<FieldBuilder>,
+    /// Used to render the actual form field, e.g.: TextInput, Switch...
+    child: Div,
+    visible: bool,
+    required: bool,
+    /// Alignment of the form field.
+    align_items: Option<AlignItems>,
+    props: FieldProps,
+}
+
+impl FormField {
+    pub fn new() -> Self {
+        Self {
+            id: 0.into(),
+            form: Weak::new(),
+            label: None,
+            description: None,
+            child: div(),
+            visible: true,
+            required: false,
+            no_label_indent: false,
+            focus_handle: None,
+            align_items: None,
+            props: FieldProps::default(),
+        }
+    }
+
+    /// Sets the label for the form field.
+    pub fn label(mut self, label: impl Into<FieldBuilder>) -> Self {
+        self.label = Some(label.into());
+        self
+    }
+
+    /// Sets not indent with the label width (in Horizontal layout).
+    ///
+    /// Sometimes you want to align the input form left (Default is align after the label width in Horizontal layout).
+    ///
+    /// This is only work when the `label` is not set.
+    pub fn no_label_indent(mut self) -> Self {
+        self.no_label_indent = true;
+        self
+    }
+
+    /// Sets the label for the form field using a function.
+    pub fn label_fn<F, E>(mut self, label: F) -> Self
+    where
+        E: IntoElement,
+        F: Fn(&mut WindowContext) -> E + 'static,
+    {
+        self.label = Some(FieldBuilder::Element(Rc::new(move |cx| {
+            label(cx).into_any_element()
+        })));
+        self
+    }
+
+    /// Sets the description for the form field.
+    pub fn description(mut self, description: impl Into<FieldBuilder>) -> Self {
+        self.description = Some(description.into());
+        self
+    }
+
+    /// Sets the description for the form field using a function.
+    pub fn description_fn<F, E>(mut self, description: F) -> Self
+    where
+        E: IntoElement,
+        F: Fn(&mut WindowContext) -> E + 'static,
+    {
+        self.description = Some(FieldBuilder::Element(Rc::new(move |cx| {
+            description(cx).into_any_element()
+        })));
+        self
+    }
+
+    /// Set the visibility of the form field, default is `true`.
+    pub fn visible(mut self, visible: bool) -> Self {
+        self.visible = visible;
+        self
+    }
+
+    /// Set the required status of the form field, default is `false`.
+    pub fn required(mut self, required: bool) -> Self {
+        self.required = required;
+        self
+    }
+
+    /// Set the focus handle for the form field.
+    ///
+    /// If not set, the form field will not be focusable.
+    pub fn track_focus(mut self, focus_handle: FocusHandle) -> Self {
+        self.focus_handle = Some(focus_handle);
+        self
+    }
+
+    pub fn parent(mut self, form: &Rc<Form>) -> Self {
+        self.form = Rc::downgrade(form);
+        self
+    }
+
+    /// Set the properties for the form field.
+    ///
+    /// This is internal API for sync props from From.
+    fn props(mut self, ix: usize, props: FieldProps) -> Self {
+        self.id = ix.into();
+        self.props = props;
+        self
+    }
+
+    /// Align the form field items to the start, this is the default.
+    pub fn items_start(mut self) -> Self {
+        self.align_items = Some(AlignItems::Start);
+        self
+    }
+
+    /// Align the form field items to the end.
+    pub fn items_end(mut self) -> Self {
+        self.align_items = Some(AlignItems::End);
+        self
+    }
+
+    /// Align the form field items to the center.
+    pub fn items_center(mut self) -> Self {
+        self.align_items = Some(AlignItems::Center);
+        self
+    }
+}
+impl ParentElement for FormField {
+    fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
+        self.child.extend(elements);
+    }
+}
+
+impl RenderOnce for FormField {
+    fn render(self, cx: &mut WindowContext) -> impl IntoElement {
+        let layout = self.props.layout;
+
+        let label_width = if layout.is_vertical() {
+            None
+        } else {
+            self.props.label_width
+        };
+        let has_label = !self.no_label_indent;
+
+        #[inline]
+        fn wrap_div(layout: Axis) -> Div {
+            if layout.is_vertical() {
+                v_flex()
+            } else {
+                h_flex()
+            }
+        }
+
+        #[inline]
+        fn wrap_label(label_width: Option<Pixels>) -> Div {
+            h_flex()
+                .truncate()
+                .when_some(label_width, |this, width| this.w(width).flex_shrink_0())
+        }
+
+        let gap = match self.props.gap {
+            Some(v) => v,
+            None => match self.props.size {
+                Size::Large => px(8.),
+                Size::XSmall | Size::Small => px(4.),
+                _ => px(4.),
+            },
+        };
+        let inner_gap = if layout.is_horizontal() {
+            gap
+        } else {
+            gap / 2.
+        };
+
+        v_flex()
+            .flex_1()
+            .gap(gap / 2.)
+            .child(
+                // This warp for aligning the Label + Input
+                wrap_div(layout)
+                    .id(self.id)
+                    .gap(inner_gap)
+                    .when_some(self.align_items, |this, align| {
+                        this.map(|this| match align {
+                            AlignItems::Start => this.items_start(),
+                            AlignItems::End => this.items_end(),
+                            AlignItems::Center => this.items_center(),
+                            AlignItems::Baseline => this.items_baseline(),
+                            _ => this,
+                        })
+                    })
+                    .when(has_label, |this| {
+                        // Label
+                        this.child(
+                            wrap_label(label_width)
+                                .text_sm()
+                                .when_some(self.props.label_text_size, |this, size| {
+                                    this.text_size(size)
+                                })
+                                .font_medium()
+                                .gap_1()
+                                .items_center()
+                                .when_some(self.label, |this, builder| {
+                                    this.child(builder.render(cx)).when(self.required, |this| {
+                                        this.child(div().text_color(cx.theme().danger).child("*"))
+                                    })
+                                }),
+                        )
+                    })
+                    .child(div().w_full().child(self.child)),
+            )
+            .child(
+                // Other
+                wrap_div(layout)
+                    .gap(inner_gap)
+                    .when(has_label && layout.is_horizontal(), |this| {
+                        this.child(
+                            // Empty for spacing to align with the input
+                            wrap_label(label_width),
+                        )
+                    })
+                    .when_some(self.description, |this, builder| {
+                        this.child(
+                            div()
+                                .text_xs()
+                                .text_color(cx.theme().muted_foreground)
+                                .child(builder.render(cx)),
+                        )
+                    }),
+            )
+    }
+}
+impl RenderOnce for Form {
+    fn render(self, _: &mut WindowContext) -> impl IntoElement {
+        let props = self.props;
+
+        let gap = match props.size {
+            Size::XSmall | Size::Small => px(6.),
+            Size::Large => px(12.),
+            _ => px(8.),
+        };
+
+        v_flex().w_full().gap(gap).children(
+            self.fields
+                .into_iter()
+                .enumerate()
+                .map(|(ix, field)| field.props(ix, props)),
+        )
+    }
+}

crates/ui/src/lib.rs

@@ -23,6 +23,7 @@ pub mod divider;
 pub mod dock;
 pub mod drawer;
 pub mod dropdown;
+pub mod form;
 pub mod history;
 pub mod indicator;
 pub mod input;